private void SetControlStates()
{
specificationGroupControl.Visible = false;
specificationControl.Visible = false;
if (_specificaionItem is Feature)
specificationControl.Visible = true;
else if (_specificaionItem is Typical)
specificationControl.Visible = true;
else if (_specificaionItem is Nominal)
specificationControl.Visible = true;
else if (_specificaionItem is Characteristic)
specificationControl.Visible = true;
else if (_specificaionItem is Guaranteed)
specificationControl.Visible = true;
else if (_specificaionItem is SpecificationGroup)
specificationGroupControl.Visible = true;
}